Engineering Applications of Multi-Dimensional CFD Analysis of Lubrication System

This paper reports on a rigorous, transient, three-dimensional CFD analysis of the complete lubrication system of automotive internal combustion engines. The computational domain of such a model is vast and includes scores of bearings as well as components such as the pump, pressure relief valve, oil filter, oil cooler, piston cooling jets etc. Thus far, the only publication on 3D CFD analysis of a complete engine lubrication system was for a 16-cylinder engine in which the feasibility and the potential engineering opportunities of such a model were demonstrated. The timelines for setting up and running such a complex CFD model are comparable to that of a 1D model. In this paper, the following four topics will be addressed: 1. Showcase the capability of the CFD software tool to accurately, robustly and reliably predict the engine lube system performance of a wide variety of automotive engines with same set of input constants i.e. no tuning. Best analysis practices were developed in order to achieve this goal by compensating for the variabilities that arise in a complex system level CFD model that connects scores of components across far flung locations in the engine lube system. The predicted pressures were validated at different locations in the lube system. Of the several engines that were considered in this study, in this paper, the results of three of them will be presented. Two of these engines are 4-cylinder while the third was a 6-cylinder engine. 2. The model can be used to quantify the effect of pump and bearing clearances on the pressure and flow rates at various components in the system. 3. The model was used to rank the performance of four different pump designs for a given engine lubrication system, i.e. pump selection. 4. The model was used to study cold start pump priming, estimate oil filling times and predict pressures in the system. The analysis engineer will now have a new tool in his analysis “tool box” increasing the impact of analysis in engine lube system design and development.